Muting a grand

[Isaac OLEG]

Sarah ,

Thanks for that information, pure heavy latex  squares I use, they are
cheap, I don't now how much they cut in the spectra, but the
vibrations of the bass are attenuated.

What about the glass casters that where used under the pianos in
Europe (grand's or verticals). How do they work ? I never been
convinced by them, but they may be efficient in some way ?

Best

Isaac OLEG

Entretien et réparation de pianos.

PianoTech
17 rue de Choisy
94400 VITRY sur SEINE
FRANCE
tel : 033 01 47 18 06 98
fax : 033 01 47 18 06 90
cell: 06 60 42 58 77

> -----Message d'origine-----
> De : pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org]De la
> part de Sarah Fox
> Envoyé : mercredi 7 mai 2003 15:21
> À : Pianotech
> Objet : Re: Muting a grand
>
>
> > plus big caster cups set on foam
>
> -- or on carpet squares, which won't mash as flat and will
> be somewhat
> springier
>
> Along the same vein, place the legs at least a foot from
> any wall.  I had a
> Rhodes Stage 88 electric piano in college for its
> portability.  I was
> actually a kind neighbor and did all my practicing through
> headsets.  One
> day I received a knock on the door from the frazzled
> downstairs neighbor who
> couldn't take my practicing any more.  It turns out the
> rear legs of the
> piano were sitting close enough to the wall that the minute
> vibrations were
> beautifully coupled into the lower wall, which served as a
> sounding board.
> After six inches of movement away from the wall, he
> couldn't hear me at all.
>
> There are also muting blankets, but I think they're only
> good for 6 dB or
> so.
>
> Contrary to popular understanding, here are the generally
> accepted rules of
> thumb regarding materials:
>
> To decouple vibrations from between solid objects, insert something
> mushy/squishy/springy -- like foam.
>
> However, to block airborne vibrations, don't use foam.  Air
> passes right
> through it.  Use dense materials with lots of weight to
> them.  Heavy felt
> (REALLY heavy) is ideal.  Think in terms of that stuff they
> use under the
> carpets of cars.  Heavy carpet is perhaps a more cosmetic solution.
>
> To keep a solid surface (e.g. a wall) from vibrating in
> response to airborne
> sound, add mass to reduce its compliance.
>
> To absorb sound instead of reflecting it back into the
> room, use a gradation
> of materials, starting from light open-cell foam, to denser
> open-cell foam,
> to heavy, thick felt, to a heavy, solid substrate such as 3/4" or 1"
> particle board.  Foam wedges are effective too, but not as
> much as people
> think.
>
> If the client is, say, a concert pianist who practices 8 hr
> a day, he or she
> might consider a sound attenuating chamber (called an
> "anechoic chamber," a
> misnomer) from Industrial Acoustics.  Really nice stuff,
> but kinda pricey.
> The chamber breaks apart into panels for shipment and
> assembly.  Even
> someone in the same room as the chamber will only hear a
> faint tinkling.
> The chamber is also an ideal "dead room" for recording and
> would probably
> serve as a bioisolation shelter in the event of a terrorist
> attack! <grin>
> If floor vibrations are a problem, the chamber can be set
> down on 1" wood
> spacers -- enough to slip small innertubes underneath the
> corners.  Inflate
> the innertubes to just enough lift the booth off of the
> spacers and provide
> a spring action.  (The spacers are important to allow
> intertubes to be
> replaced without disassembling the booth.
>
> Hope that helps.
>
> Peace,
> Sarah
>
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